moles and percent comp rreview

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What is a mole in chemistry?

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A mole is a unit of measurement used to express the amount of a substance. It is defined as the amount of substance that contains as many entities (atoms, molecules, etc.) as there are in 12 grams of carbon-12.

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How do you calculate the number of moles from volume of gas at STP?

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At standard temperature and pressure (STP), 1 mole of any gas occupies 22.4 liters. To find the number of moles, divide the volume of the gas by 22.4 L.

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What is the formula to calculate percent composition by mass?

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Percent composition by mass = (mass of element in 1 mole of compound / molar mass of compound) x 100%.

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How do you find the number of particles in a mole?

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The number of particles in a mole is given by Avogadro's number, which is approximately 6.022 x 10^23 particles per mole.

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What is the molar mass of a compound?

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The molar mass of a compound is the mass of one mole of that compound, calculated by summing the atomic masses of all the atoms in its formula.

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How many moles are in 70 L of O2 gas at STP?

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3.1 mol O2 (calculated using the formula: moles = volume (L) / 22.4 L/mol).

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How many particles are in 8.4 moles of Octane (C8H18)?

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5.04 x 10^24 particles (calculated using Avogadro's number: particles = moles x 6.022 x 10^23).

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How many moles are in 4.7 L of NO gas at STP?

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0.21 mol NO (calculated using the formula: moles = volume (L) / 22.4 L/mol).

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What is the percent composition by mass of sulfur (S) in MgSO4?

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26.64% (calculated using the formula for percent composition).

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What is the molar mass of PbSO4?

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303.3 g/mol (calculated by adding the atomic masses of Pb, S, and O in the formula).